Variable hardness support for sheet to be printed



Aug. 8, 1967 VARIABLE HARDNESS SUPPORT FOR SHEET TO BE PRINTED M. L.JAFFA ETAL Filed Feb. 24, 1965 FIG. 2 A A 10 1 14 I5 4 14 M w -iv." H 12I L y s w/ I H INVENTORS MaHhew L. Jaffa David Jaffa ATTORNEY UnitedStates Patent 3,334,586 VARIABLE HARDNESS SUPPORT FOR SHEET TO BEPRINTED Matthew L. Jaffa, 92 Clark St., Rutherford, NJ. 07070, and DavidJalfa, 38--26 Allwood Place, Fair Lawn, NJ. 07410 Filed Feb. 24, 1965,Ser. No. 434,832 7 Claims. (Cl. 101407) This invention relates to aprinting surface and more specifically to a screen printing surface inwhich the hardness or softness of the surface can be varied as desiredfor obtaining optimum printing results.

In screen printing the hardness or softness of a printing surface onwhich the screen printing operation is being conducted is very importantin the determination of a desired effect or depth of col-or in thefinished screen print. Heretofore, in screen printing it was necessaryfor the printer to choose between either a hard surface or a softsurface when building or using a screen printing machine or a handprinting table. Thus, the use of a machine or table constructed witheither specific hard surface of soft printing surface was limited in itsuse to that type of printing for which the' given printing surface wasdesigned. Consequently, it was heretofore necessary for a printer tohave on hand machines and/or tables with a hard printing surface, a softprinting surface or surfaces of intermediate softness or hardness inorder to accommodate for both hard and soft screen type printing. Oftentimes it would be desirable to have printing surfaces of variousintermediate hardnesses or softnesses. Because a given printer would notnormally have on hand a printing surface of all the desired hardnessesor softnesses to attain all the desired color or printing effects, itwas necessary for such printer to compromise the desired end results inaccordance with the hardness or softness of the printing surfaces onhand. Consequently the optimum results for varying the possible coloringor printing effects were not readily obtainable with the known printingsurfaces, unless the printer had on hand a relatively large number oftables or machines each formed with a surface of variable hardness orsoftness.

It is therefore an object of this invention to provide a printingsurface in which the degree of hardness or softness thereof can bevaried at will.

It is another object to provide a printing surface in which the degreeof hardness or softness of the surface can be obtained by controllingthe differential in pressures acting thereon.

It is another object to provide a printing surface of variable hardnessor softness which is relatively simple in construction, relativelyinexpensive to manufacture and which is positive in operation.

The foregoing objects and other features and advantages of thisinvention are obtained by a printing surface capable of attainingvariable degrees of hardness or softness comprising of a relativelyrigid supporting surface on which there is disposed a sheet ofrelatively deformable or flexible air impervious material to definetherewith a collapsible vacuum chamber. Enclosed within the vacuumchamber is a padding or thickness of a readily compressible or porousmaterial. A printing blanket may be disposed over the sheet ofimpervious sheet material. In accordance with this invention, a sourceof negative pressure, as for example a vacuum pump or the like, isconnected in communication with the vacuum chamber by a suitableconnecting conduit so that a vacuum may be drawn on the vacuum chamberas desired. The arrangement is such that when the vacuum is drawn byoperation of the negative pressure source, the force of 3,334,586Patented Aug. 8, 1967 ice the atmospheric air acting externally of thevacuum chamber defined will cause the padding material in the vacuumchamber to be compressed thereby varying the hardness or softness of theprinting surface accordingly.

A feature of this invention resides .in the provision of a printingsurface comprising of a readily deformable vacuum chamber in which thereis enclosed a compressible material that is readily compressed to thedesired degree of hardness or softness by the external atmosphere actingthereon depending upon the degree of vacuum that is pulled on the vacuumchamber.

Another feature of this invention resides in the provision of a printingsurface in which the degree of hardness and/or softness thereof can beinfinitely controlled between the maximum softness and maximum hardnessof the compressible material so as to obtain the optimum printingsurface for attaining the desired end results or effects.

Still another feature of this invention is to provide a common printingsurface which is particularly adapted to perform both hard and softscreen printing.

Other features and advantages will become more readily apparent whenconsidered in view of the drawings in which:

FIGURE 1 illustrates a cross-sectional view of the printing surface ofthe instant invention illustrated in its maximum soft position.-

FIGURE 2 is a cross-sectional view of the printing surface similar tothat shown in FIG. 1, but illustrating the arrangement thereof in itsmaximum hard position.

Referring to the drawings, there is shown the improved printing surface10 of the instant invention. The printing surface 10 disclosed isparticularly adapted for use in the screen printing art. Accordingly,the surface 10 to be herein described can be readily adapted to a screenprinting machine or to a hand printing table.

In screen printing it is possible to create different desired effectsfor particular colors depending upon the hardness or softness of theprinting surface on which a screen printing operation is beingperformed. Heretofore, it was necessary for a printer to choose betweeneither a hard surface or a soft surface prior to performing the screenprinting operation depending upon the desired end effect or depth ofcolor desired. In accordance with this invention, there is provided animproved screen printing surface 10 in which hardness or softness of theprinting surface can be readily varied at will so as to obtain theoptimum results for a given effect or depth of color. Also, with theinstant invention it is possible to create different surfaces at varyingpoints along the printing surface so that each color can have thenecessary degree of hardness or softness required to produce the desiredeffect or a particular color.

Referring more specifically to the drawings, there is shown therein arelatively rigid support member or top 11 which constitutes the backingor table support of the printing surface 10 to be described. In theillustrated embodiment a layer of smooth, hard, air impervious material,as for example, a laminated plastic material, such as Formica 12, isdisposed in overlying relationship to the top of the rigid supportmember 11. Accordingly, there is disposed in overlying relationship tothe support member a sheet of relatively thin flexible or deformable airimpervious material or cover 13 of such non-porous material such aspolyethylene, Mylar, or Vinyl. Accordingly, the cover 13 or sheet ofnon-porous material is substantially co-extensive in length to thelength of the printing surface in which the peripheral or marginalportion of the flexible sheet 13 is suitably secured to the supportingsurface by any suitable means so as to define an air tight vacuumchamber 14 between the table top 12 and the sheet 13 of the deformablematerial.

Encased within the vacuum chamber 14 there is provided a layer ofcompressible material or padding 15 which is substantially co-extensivewith the top of the table support member. Accordingly, the paddingmaterial 15 may comprise of any spongeable or readily compressiblematerial, such as foam rubber, sponge, polyurethane, felt or any otheropen or cellular type material. The printing blanket 16 is thenpositioned in superposed relationship with the upper surface of thedeforma ble sheet material 13, the printing blanket 16 forming thesurface on-which the material to be screen printed is rested during ascreen printing operation.

In accordance with this invention, a means is provided for drawing avacuum on the vacuum chamber 14. In the illustrated embodiment, themeans comprises a source of negative pressure, as for example a vacuumpump 17, which has its inlet connected to a manifold 18 to which one ormore conduits 19, 19A, 19B are suitably connected in communication withport openings 20 formed in the bottom of the rigid supporting member 11.Accordingly, the conduits 19B are connected in open communication withthe vacuum chamber 14.

The arrangement is such that whenever the source of negative pressure 17is rendered operative, the suction created thereby tends to withdraw theair from within the vacuum chamber 14, thereby resulting in a negativepressure occurring within the vacuum chamber 14. The atmosphericpressure thus acting externally of the vacuum chamber as indicated byarrows A causes the vacuum chamber 14 and the padding material 15therein to be compressed as indicated in FIG. 2. Depending upon thedegree of vacuum which is pulled on the chamber 14, the hardness orsoftness of the compressible material 15 is varied accordingly.

As shown in FIG. 1, the maximum softness of the printing surface 10described is established primarily by the normal hardness or softness ofthe compressible material 15 disposed within the vacuum chamber 14. Itwill therefore be apparent that as the degree of vacuum pulled on thevacuum chamber is increased, the hardness of the compressible material15 is increased accordingly. Thus, the atmospheric air pressure actingexternally on the chamber 14 compresses the padding material 15 so thatmaximum hardness is obtained when a minimum negative pressure is createdin the vacuum chamber 14.

From the foregoing, it will therefore become readily apparent that aprinter may vary the desired degree of hardness or softness of theprinting surface 10 described, to obtain the optimum end results oreffects desired for any particular screen printing operation and/orcolor effect. Thus, it will also be noted that the degree of hardness orsoftness of the printing surface 10 defined can be infinitely controlledbetween the maximum softness position as indicated in FIG. 1 and themaximum hardness position as indicated in FIG. 2, merely by controllingthe degree of vacuum which is pulled on the vacuum chamber 14.Consequently, with a single printing surface of the type hereindescribed, a printer may obtain all of the desired effects and colorvariations desired for any degree of hardness or softness, which washeretofore not obtainable with a single or common screen printingsurface.

While the instant invention has been described with reference to aparticular embodiment thereof, it will be readily appreciated andunderstood that variations and modifications of the invention may bemade without departing from the spirit or scope of the invention.

What is claimed is:

1. A printing surface of variable hardness compris- (a) a rigid backingmember,

(b) imperforate, air impervious means defining a deformable vacuumchamber impervious to a pulled vacuum thereon supported on said backingmemher,

(c) a compressible padding means disposed between said backing memberand imperforate, air impervious means so as to be confined within saidvacuum chamber,

(d) and means for drawing a vacuum on said chamber causing theatmospheric pressure acting externally on said deformable vacuum chamberand padding means therein to compress so as tovary the hardness of theprinting surface defined thereby in accordance with the degree of vacuumpulled on said vacuum chamber.

2. A means for varying the hardness of a printing surface comprising:

(a) a rigid supporting surface,

(b) means in the form of a compressible mat overlying said supportingsurface,

(c) an air impervious flexible sheet of material overlying said mat toform an enclosure encasing said mat between said supporting surface andsaid flexible sheet,

(d) and means connected in communication with said enclosure forevacuating the air from said enclosure whereby said mat is compressed bythe external atmospheric pressure acting thereon to vary the hardness ofsaid mat in accordance with the degree of vacuum pulled on saidenclosure.

3. The invention as defined in claim 2 and said latter means including aconduit connected in communication with said vacuum chamber,

and a source of negative pressure connected to the other end of saidconduit for creating the vacuum on said enclosure.

4. The invention as defined in claim 2 wherein said mat is formed ofcell lar material.

5. The invention as defined in claim 4 and including:

a printing blanket overlying the sheet of air impervious material.

6. A printing surface for printing a design on a sheet of materialcomprising:

(a) a smooth flat table top surface,

(b) an imperforate sheet of readily deformable air impervious materialoverlying said table top surface,

(0) means for securing the marginal portion of said sheet of airimpervious sheet material to said table top surface, said sheet sosecured being impervious to a pulled vacuum thereon to definetherebetween a vacuum chamber,

((1) a pad of readily compressible material overly ing the area of saidtable top surface within said vacuum chamber,

(e) and means for drawing a vacuum on said chamber so that as the vacuumon said chamber is drawn, the external pressure acting on said airimpervious sheet causes said vacuum chamber and compressible paddingtherein to compress toward said rigid table top surface to thereby varythe hardness of the printing surface in accordance with the vacuumdrawn.

7. A variable printing surface comprising:

(a) a rigid table top,

(b) a laminate of smooth, flat, air impervious material connected tosaid table top to define a rigid support,

(0) a thickness of a compressible padding overlying said laminate,

(d) an imperforate sheet of readily deformable air impervious materialcovering said compressible padding,

(e) means for securing the peripheral portions of said sheet to saidrigid support to define an enclosed vacuum chamber impervious to avacuum pulled thereon about said padding,

(f) and means for drawing a vacuum on said chamber whereby theatmospheric pressure acting on said sheet material causes said paddingto be compressed in 5 6 accordance to the degree of vacuum drawn on saidReferences Cited chamber UNITED STATES PATENTS (g) said latter meansincluding a conduit connected in communication With said vacuum chamber,1,426,471 8/1922 P1135611 101407 X (h) and a source of negative pressureconnected to the 5 2,956,769 10/1960 slgler et 248 363 other end of saidconduit for creating the vacuum 3,126,192 3/1964 Stem 248 362 on saidchamber, (i) and a printing blanket overlying said deformable ROBERTPULFREY Primary Exammer' sheet. H. P. EWELL, Assistant Examiner.

1. A PRINTING SURFACE OF VARIABLE HARDNESS COMPRISING: (A) A RIGIDBACKING MEMBER, (B) IMPERFORATE, AIR IMPREVIOUS MEANS DEFINING ADEFORMABLE VACUUM CHAMBER IMPREVIOUS TO A PULLED VACUUM THEREONSUPPORTED ON SAID BACKING MEMBER, (C) A COMPRESSIBLE PADDING MEANSDISPOSED BETWEEN SAID BACKING MEMBER AND IMPERFORATE, AIR IMPERVIOUSMEANS SO AS TO BE CONFINED WITHIN SAID VACUUM CHAMBER, (D) AND MEANS FORDRAWING A VACUUM ON SAID CHAMBER CAUSING THE ATMOSPHERIC PRESSURE ACTINGEXTERNALLY ON SAID DEFORMABLE VACUUM CHAMBER AND PADDING MEANS THEREINTO COMPRESS SO AS TO VARY THE HARDNESS OF THE PRINTING SURFACE DEFINEDTHEREBY IN ACCORDANCE WITH THE DEGREE OF VACUUM PULLED ON SAID VACUUMCHAMBER.